Untapped potential: Mushroom beta-glucans backed for bright functional future

While using mushrooms as a source of beta-glucans is not new, per se​, the Indian research team behind the study suggest that there is a huge amount of untapped potential for functional food ingredients in fungi.

Writing in Bioactive Carbohydrates and Dietary Fibre​, the team noted that the content of beta-glucans in mushrooms have been shown to range from 0.21 to 0.53 grams per 100 grams – with the highest levels found immediately before the spores begin to mature.

They added that the beta-glucans in mushrooms may have a wide variety of health benefits and functional applications as nutritional bioactives.

“Mushrooms can be viewed as an important source of bioactive polysaccharides like beta-glucans,” ​wrote the team – led by Asma Ashraf Khan at the University of Kashmir, India. “Mushroom beta-glucans have potential nutraceutical properties that could be explored in the food and the pharmaceutical fields and might present different functional properties upon modification through suitable means.”​

Mushroom beta-glucans​

The team behind the study noted that while beta-glucans from other sources like yeasts and cereals are well known and have been extensively investigated in scientific literature, mushroom beta-glucans are ‘not well documented.’

“Mushroom beta-glucans provide a unique opportunity for the discovery of novel therapeutic agents and have attracted a great deal of attention due to many health benefits,”​ said the team – noting that mushrooms beta-glucans have been suggested to have multiple beneficial properties including the potential to enhance innate and cell mediated immune responses and antimicrobial activities.

They noted that most beta-glucans in mushrooms are insoluble, and generally make up between 54% and 82% of total beta-glucan content while soluble beta-glucans range between 16% and 46% in general.

Several beta-glucans isolated from mushrooms have already been identified and are being manufacturered by industry, note the team. However, they add that there is undoubted potential for further discovery and development of mushroom beta-glucans.

Examples of beta-glucans already identified and in use include krestin, a beta-glucan obtained from Coriolus versicolor ​and first manufactured by the Japanese company Sankyo. Meanwhile, lentinan was derived from the fruiting bodies of Lentinus edodes​ commonly known as shiitake mushroom, and has been suggested to have significant immune modulating effects.

Other well-known mushroom beta-glucans include schizophyllan, pleuran and grifolan, the team noted.

“Mushroom beta-glucans differ in their efficacy as nutraceutical agents due to the difference in their molecular masses, solubility, degree of polymerization, their structures and helical conformation,”​ wrote the Indian team.

“Future research can be directed to modify mushroom beta-glucans so as to improve their nutraceutical potential,”​ they added.

Functional potential​

Ashraf Khan noted that around 200 glucans have been isolated from the fruiting bodies, spores, mycelia and cultivation broth of mushrooms.

“The future challenge here now is how to identify individual beta-glucan of known structure that binds to a particular receptor, how to interpret their advanced structural features using advanced techniques so as to define their 3D structure,”​ said the team, adding that future chellenges also include the development of mushrooms with higher beta-glucan content.

“Since various mushroom beta-glucans are available as pure extracts in the market which are used as therapeutic agents, however, no commercialised functional products are available which have been fortified with mushroom beta-glucans,”​ they noted. “It has a great potential to be used as an ingredient in the near future in various food industries, such as breakfast cereals, sport nutrition products, dairy products, bakery such as biscuits and breads.” ​

Indeed, the Indian team noted that various studies have already begun to explore the possibility of utilising mushroom beta-glucans in a wide variety of nutritional products including yoghurts, baked products, noodles, and extruded snacks.

Source: Bioactive Carbohydrates and Dietary Fibre​
Published online ahead of print, doi: 10.1016/j.bcdf.2017.12.002​
“Biological and pharmaceutical activities of mushroom β-glucan discussed as a potential functional food ingredient”​
Authors: Asma Ashraf Khan, et al​